Apparatus and method for transmitting broadcast channel in broadband wireless access system

Abstract

To transmit and receive system information of a base station in a broadband wireless access system, operations of the base station include determining transmission periodicities of a plurality of system information subpackets periodically transmitted in a periodicity of two or more superframes, determining transmission offsets of the subpackets based on the transmission periodicities using a predefined rule for determining a transmission periodicity and a transmission offset, and transmitting the subpackets respectively according to the transmission periodicities and the transmission offsets.

What is claimed is: 
     
       1. A method for operating a base station for transmitting system information in a wireless communication system, the method comprising:
 transmitting system information for a first periodicity and a second periodicity which is a multiple of the first periodicity; 
 transmitting a first subpacket according to the first periodicity and a first offset; and 
 if a modulo operation result of a superframe number of a superframe with the second periodicity is equal to a second offset, transmitting a second subpacket according to the second periodicity, at the superframe, 
 wherein the system information is carried in a plurality of subpackets comprising the first subpacket and the second subpacket, 
 wherein the second offset is identified as being equal to a value which is smaller than the first periodicity if the first offset is zero, and 
 wherein the second offset is identified as being equal to the first periodicity if the first offset is not zero and smaller than the first periodicity. 
 
     
     
       2. The method of  claim 1 ,
 wherein the second offset is identified by a mobile station receiving the first subpacket and the second subpacket based on the first periodicity and the first offset. 
 
     
     
       3. The method of  claim 1 , wherein transmitting the system information for the first periodicity and the second periodicity comprises:
 transmitting additional information for an index before transmitting the first subpacket, 
 wherein the transmitted index indicates a row of a predefined table including a plurality of periodicity sets, 
 wherein the row indicates the first periodicity and the second periodicity among the plurality of periodicity sets, and 
 wherein the predefined table does not include a plurality of offsets corresponding to the plurality of periodicity sets. 
 
     
     
       4. The method of  claim 1 ,
 wherein the first periodicity is determined by multiplying an allotted time for a superframe by two or more, and 
 wherein the superframe comprises the system information. 
 
     
     
       5. The method of  claim 1 , wherein the transmitting of the second subpacket comprises:
 encoding the second subpacket; and 
 broadcasting the encoded second subpacket at a subframe. 
 
     
     
       6. The method of  claim 1 , further comprising:
 transmitting a third subpacket according to a third periodicity and a third offset, 
 wherein the third periodicity is a multiple of the second periodicity, and 
 wherein the first offset, the second offset, and the third offset are identified according to an equation (1) or an equation (2)
     O   1 =0  O   1   =P   1 −1
 
     O   2   =P   1 −1 or  equation (1)
 
     O   2   =P   1   equation (2)
 
     O   3   =P   2 −1  O   3   =P   2  
 
 
 where O 1  represents the first offset, O 2  represents the second offset, O 3  represents the third offset, P 1  represents the first periodicity, and P 2  represents the second periodicity. 
 
     
     
       7. An apparatus of a base station for transmitting system information in a wireless communication system, the apparatus comprising:
 at least one processor; and 
 at least one transceiver operatively coupled with the at least one processor, 
 wherein the at least one transceiver is configured to:
 transmit periodicity information for a first periodicity and a second periodicity which is a multiple of the first periodicity, 
 transmit a first subpacket according to the first periodicity and a first offset, and 
 transmit, if a modulo operation result of a superframe number of a superframe with the second periodicity is equal to a second offset, a second subpacket according to the second periodicity at the superframe, 
 
 wherein the system information is carried in a plurality of subpackets comprising the first subpacket, and the second subpacket, 
 wherein the second offset is identified as being equal to a value which is smaller than the first periodicity if the first offset is zero, and 
 wherein the second offset is identified as being equal to the first periodicity if the first offset is not zero and smaller than the first periodicity. 
 
     
     
       8. The apparatus of  claim 7 ,
 wherein the second offset is identified by a mobile station receiving the first subpacket and the second subpacket based on the first periodicity and the first offset. 
 
     
     
       9. The apparatus of  claim 8 , wherein the at least one processor is configured to transmit additional information for an index before the transmission of the first subpacket,
 wherein the transmitted index indicates a row of a predefined table including a plurality of periodicity sets, 
 wherein the row indicates the first periodicity and the second periodicity among the plurality of periodicity sets, and 
 wherein the predefined table does not include a plurality of offsets corresponding to the plurality of periodicity sets. 
 
     
     
       10. The apparatus of  claim 7 ,
 wherein the first periodicity is determined by multiplying an allotted time for a superframe by two or more, and 
 wherein the superframe comprises the system information. 
 
     
     
       11. The apparatus of  claim 7 , wherein the at least one processor is configured to:
 encode the second subpacket if the modulo operation result is equal to the second offset; and 
 wherein the at least one transceiver is configured to transmit the encoded second subpacket at a subframe. 
 
     
     
       12. The apparatus of  claim 7 , wherein the at least one transceiver is further configured to:
 transmit a third subpacket according to a third periodicity and a third offset, 
 wherein the third periodicity is a multiple of the second periodicity, and 
 wherein the first offset, the second offset, and the third offset are identified according to an equation (1) or an equation (2)
     O   1 =0  O   1   =P   1 −1
 
     O   2   =P   1 −1 or  equation (1)
 
     O   2   =P   1   equation (2)
 
     O   3   =P   2 −1  O   3   =P   2  
 
 
 where O 1  represents the first offset, O 2  represents the second offset, O 3  represents the third offset, P 1  represents the first periodicity, and P 2  represents the second periodicity. 
 
     
     
       13. An apparatus of a mobile station for receiving system information in a wireless communication system, the apparatus comprising:
 at least one processor; and 
 at least one transceiver operatively coupled with the at least one processor, 
 wherein the at least one transceiver is configured to:
 receive, from a base station, periodicity information for a first periodicity and a second periodicity which is a multiple of the first periodicity; and 
 receive, from the base station, a first subpacket according to the first periodicity and a first offset, and 
 
 wherein the at least one processor is configured to:
 identify a second offset as being equal to a value which is smaller than the first periodicity if the first offset is zero; and 
 identify the second offset as being equal to the first periodicity if the first offset is not zero and smaller than the first periodicity, 
 
 wherein the at least one transceiver is further configured to if a modulo operation result of a superframe number of a superframe with the second periodicity is equal to the identified second offset, receive, from the base station, a second subpacket according to the second periodicity at the superframe, 
 wherein the system information is carried in a plurality of subpackets comprising the first subpacket and the second subpacket. 
 
     
     
       14. The apparatus of  claim 13 ,
 wherein the at least one transceiver is configured to receive additional information for an index before the reception of the first subpacket, 
 wherein the index indicates a row of a predefined table including a plurality of periodicity sets, 
 wherein the row indicates the first periodicity and the second periodicity among the plurality of periodicity sets, and 
 wherein the predefined table does not include a plurality of offsets corresponding to the plurality of periodicity sets. 
 
     
     
       15. The apparatus of  claim 13 , wherein the at least one processor is configured to:
 decode the second subpacket. 
 
     
     
       16. The apparatus of  claim 13 , wherein the at least one transceiver is further configured to receive, from the base station, a third subpacket according to a third periodicity and a third offset,
 wherein the third periodicity is a multiple of the second periodicity, and 
 wherein the first offset, the second offset, and the third offset are determined according to an equation (1) or an equation (2)
     O   1 =0  O   1   =P   1 −1
 
     O   2   =P   1 −1 or  equation (1)
 
     O   2   =P   1   equation (2)
 
     O   3   =P   2 −1  O   3   =P   2  
 
 
 where O 1  represents the first offset, O 2  represents the second offset, O 3  represents the third offset, P 1  represents the first periodicity, and P 2  represents the second periodicity.